WO2010127827A1

WO2010127827A1 - Objective having two viewing directions for an endoscope

Info

Publication number: WO2010127827A1
Application number: PCT/EP2010/002717
Authority: WO
Inventors: Peter Schouwink; Tokayuki Kato
Original assignee: Olympus Winter & Ibe Gmbh
Priority date: 2009-05-07
Filing date: 2010-05-04
Publication date: 2010-11-11
Also published as: JP2012526293A; US20120127567A1; CN102422199A; DE112010001908A5

Abstract

The invention relates to an objective (1, 1') having two viewing directions (8, 10; 8'; 10') for an endoscope, comprising a first distal objective part (6, 6') directed in the first viewing direction with the axis (8, 8') thereof, a second objective part (9, 9') directed in the second viewing direction with the axis (10, 10') thereof, and a proximal objective part (2, 2') directed at an image sensor (4, 4') or an image conductor with the axis (3, 3') thereof, and further having a switching device comprising a prism (14, 14') for the switchable deflection of the radiation path from the first or the second distal objective part (6, 6'; 9, 9') into the proximal objective part (2, 2'), characterized in that the switching device comprises a beam deflection device (17, 35) that can be mechanically introduced into the beam path.

Description

Us. Characters: 05118ρct

Lens with two viewing directions for an endoscope

The invention relates to a lens referred to in the preamble of claim 1 Art.

A generic objective is known from EP 0 363 118 Bl. This shows an endoscope objective with two distal objective parts for two different viewing directions and with a common proximal objective part. As a switching device electrically switchable polarization filters are provided. The image brightness of this construction is unsatisfactory.

EP 0 347 140 B1 shows a lens with two viewing directions, between which is mechanically switched by pivoting the image guide relative to the lens. Obviously, the design effort is enormous.

The object of the present invention is to enable a viewing direction switching in a generic lens in a simple manner and with good image brightness.

This object is achieved with the features of the characterizing part of claim 1.

According to the invention, a beam deflection device can be mechanically brought into the beam path for switching. In this way, the disadvantages of the two aforementioned structures can be avoided. It must only an optical component are moved and the optical disadvantages of polarizing filters are avoided.

Preferably, according to claim 2, the optical path length through the lens is the same in both directions. This simplifies the optical conditions.

In lenses of the type in question here sits at the distal end of each of the two distal lens parts a strong negative refractive lens, which produces strong aberrations. These are corrected in the proximal objective part, which must be adapted to the distal objective part for correction. Advantageously, therefore, the features of claim 3 are provided. With identical except for possible reflections beam path in the two distal lens parts ensures that both distal lens parts are compensated correctly by the corrective measures in the proximal lens part with respect to aberrations.

Advantageously, according to claim 4, the interface of a prism is alternately switched reflective or permeable. For this purpose, a mirror arranged parallel to the boundary surface is used, which can be moved into or out of the beam path, thus either causing the desired reflection or, in its absence, allowing the beam path to pass through the boundary surface. This results in a structurally very simple solution, with very good image brightness.

Advantageously, the features of claim 5 are provided. This ensures that only the switchable mirror determines whether or not it is reflected at the interface.

The surfaces of the first gap are generally oblique to the lens axis. This results in a slight parallel displacement of the beam path to a slight change in the viewing direction leads. Advantageously, therefore, the features of claim 6 are provided. A second gap with the reverse oblique direction compensates for the parallel offset of the first gap, so that the resulting viewing direction of the objective runs exactly as desired exactly straight.

Advantageously, the features of claim 7 are provided. This results in a construction of the prism, in which the proximal objective part lying exit surface in the area in which the beam path to the proximal objective part to escape is permeable, but next to the inside is reflective, so that there the deflection of the beam path for the second line of sight can take place.

The reflective embodiment according to claim 7 may, for. B. be effected by a reflective coating of the exit surface in this area or advantageous according to claim 8, characterized in that the reflective area is formed totally reflecting. For this, the refractive index of the prism and the reflection angle must be selected accordingly.

The mirror should be as close as possible to the interface so that nothing disturbing can intervene. But then there is the danger of interference. The gap between the mirror and the interface must not be too narrow. It should be advantageous according to claim 9 over lμm and in particular advantageously be greater than 5 microns according to claim 10.

The mirror used for switching between the viewing directions is advantageously designed in accordance with claim 11 in assembly with an adjacent diaphragm, so that when moving the mirror from the beam path, the diaphragm is brought into the beam path. It is then dimmed with this aperture of the current direction in the first straight looking beam path, which leads to a significant design simplification. The Strahlumlenkeinrichtung can also in a very different way, for. B. as a mirror or as an additional prism and is advantageously formed according to claim 12. In this case, the prism has two areas that can be brought alternately into the beam path and provide different, adapted to the two distal lens parts deflections. To switch, the prism must be moved only so far that it enters with its first or with its second area in the beam path. In a preferred embodiment, the prism may be formed in one area as a plane plate and pass straight through the beam path, while it is formed in the other area as the actual prism.

An advantageous construction is shown in claim 13 for an objective in which the first objective part is oriented straight ahead in the direction of the axis of the proximal objective part. In this case, the first region of the prism is formed with parallel end faces as a plane plate, which passes unobstructed the beam path of the first distal lens part.

The mechanical displacement of the prism can be done in different ways, for example by rotation or the like, but is advantageously designed according to claim 14, namely as a displacement transversely to the axis of the proximal objective part.

According to claim 15, one or both distal lens parts may be connected for common movement with the prism. This can be z. B. improve the design with respect to the optical adjustment and there are different design options also in terms of space requirements in the cramped interior of an endoscope.

In the drawing, the invention is shown for example and schematically. Show it: Fig. 1 is a side view of an objective according to the invention in the first

Embodiment in switching position of the oblique viewing direction,

2 is a view according to FIG. 1 in the switching position of the straight ahead

Sight,

3 is a plan view of the apparent in Figs. 1 and 2 mirror in a variant with adjacent aperture,

4 is a highly schematic representation of an objective according to the invention in a second embodiment in a first switching position, and

Fig. 5, the lens of Fig. 4 in a second switching position.

Fig. 1 shows an inventive lens 1 of a first embodiment, which consists of three objective parts.

A proximal objective part 2 is arranged with its axis 3 in the axis of the shaft, not shown, of an endoscope, in the distal end region of which the objective 1 is arranged. The proximal objective part 2 consists of a plurality of lenses and, together with one of two distal objective parts through a glass plate 5, produces an image in an image plane 4 which can carry, for example, an electronic image sensor. The image plane 4 may also be an intermediate image plane from which a conventional image guide, z. B. an image guide with a relay lens assembly that transmits image to a proximal endoscope arranged on the eyepiece.

In the distal region of the lens 1, a first distal lens part 6 is arranged, which by a window 7 of the endoscope not otherwise shown with its axis 8 parallel to the axis 3 of the proximal objective part, ie in the direction of the axis of the endoscope, looking straight ahead. Further, a second distal lens part 9 is provided, which looks with its axis 10 in a second oblique viewing direction through a window 11.

The second distal objective part 9 has at its distal end a negative-refractive lens 12 which sits on an input face 13 of a prism 14. The illustrated in Fig. 1, from the oblique viewing direction of the axis 10 incident beam path is reflected at a perpendicular to the axis 3 of the proximal objective part exit surface 15 of the prism 14 and thrown onto an interface 16 of the prism 14, from where after repeated reflection of the beam path is brought in the direction of the axis 3 of the proximal objective part 2, to enter through the exit surface 15 of the prism 14 in the proximal objective part 2, where it is imaged with the illustrated beam path on the image plane 4.

The incident in the direction of the axis 10 in the oblique viewing direction, shown in Fig. 1 beam path is thus reflected twice inside the prism 14 and once at the exit surface 15 and then at the interface 16. Since the first distal lens part 6 no Reflection takes place and reflected twice in the second distal lens part 9, results in the same image orientation in both distal lens parts, eg in both cases upright image or in both cases upside down image.

In the reflective region of the exit surface 15, in which the inner reflection must take place, the exit surface 15 z. B. be mirrored from the outside. However, this reflective coating must then not extend into the region in which the beam path should pass after reflection at the interface 16 in the direction of the proximal objective part 2. An elegant solution to this problem, as shown in FIG. 1, is not to define the exit surface 15. but to choose the refractive index of the prism 14 and the reflection angle at the exit surface 15 such that total reflection occurs.

As shown in FIG. 1, the reflection angle for the second reflection, which takes place at the interface 16, is chosen to be very acute, so that no total reflection can occur here. The light rays striking the interface 16 from the inside thus pass through them. The reflection of the light rays at the interface 16 shown in Fig. 1 must therefore be effected by other means.

It is for this purpose, as shown in FIGS. 1 and 2, one of the interface 16 abutting mirror 17 is provided, which is formed mirrored to the interface 16 out. 1 and 2 show two switching positions of the mirror 17. In the position in Fig. 1, the mirror sits in the beam path and causes the back reflection of the rays shown in Fig. 1.

Fig. 2 shows the unchanged construction of Fig. 1 in the same view, wherein only the switching position of the mirror 17 is changed.

In the position shown in FIG. 2, the mirror 17 is pushed to the side. The beam path entering obliquely in the direction of the axis 10 through the second distal objective part 9 is no longer reflected inwardly at the boundary surface 16 in the direction of the proximal objective part 2, but exits through the boundary surface 16 and runs out of space. The beam path entering through the first distal objective part 6, looking straight ahead in the direction of its axis 8 and shown in FIG. 2, which was intercepted by the rear side of the mirror 17 according to FIG. 1, can now be turned to the side in the switching position according to FIG 2 enter through the interface 16 in the prism and straight ahead in the direction of the axis 8 through the exit surface 15 to the proximal objective part 2, as shown in Fig. 2. If the mirror 17 is pushed back into the beam path as far as the position according to FIG. 1 from the position according to FIG. 2, blocking of the beam path incident through the first distal objective part 6 results again and again the beam path resulting in FIG 1 is shown. Since no total reflection takes place at the interface 16, the reflection at this point is determined solely by the switching position of the mirror 17 and can thereby be selectively controlled.

In the embodiment of Figs. 1 and 2, the mirror 17 is formed as a simple plane mirror which is slidably movable on the interface 16 of the prism 14 between the two switching positions of Figs. 1 and 2, with a direction of movement in the plane of the drawing.

However, the mirror 17 could also be moved in the direction perpendicular to the plane of the drawing. It could then, as shown in Fig. 3, be arranged in a sliding plate 18 in unit with a diaphragm 19. By moving the sliding plate 18 in the direction of the arrow 20 so either either the mirror 17 or designed as a hole in the sliding plate 18 aperture 19 can be brought into the beam path.

When using the sliding plate 18 of Fig. 3, the beam path shown in Fig. 1 can be generated by the sliding plate 18 is displaced so that the mirror 17 is in the beam path, ie in position shown in FIG. 1. After displacement of the sliding plate 18 to the aperture 19 is in the beam path, results in the beam path shown in FIG. 2, which is now dimmed by the aperture 19 in the desired manner.

The mirror 17, either as a single component or as a structural unit according to FIG. 3, is displaceably arranged in the direction of the interface 16 on this. In this case, the mirror is seated in a gap between the interface 16 and the outlet surface 21 of a glass rod 22 arranged parallel to the latter and, as in FIG. 1 represented on its proximal entrance surface 23 carries a further negative refractive lens 12.

The first gap formed between the interface 16 and the exit surface 21 of the glass rod 22 results, as each gap defined between parallel surfaces, when passing through light, a parallel offset of the beam path. This leads to a slight directional shift, ie a slight tilting of the straight-ahead viewing direction.

To avoid this, a second gap 24 is drawn in dashed lines in Fig. 1, which is generated at this point by separating and pulling apart two parts of the glass rod 22. The second gap 24 is disposed at an angle to the axis 8, which is 180 ° minus the angle of the first gap. The second gap 24 causes as well as the first gap a parallel displacement of the beam path, but in the other direction as in the first gap, so that cancel the two shifts.

The mirror 17 should, at least when he is in the switching position of Fig. 1 and is in the beam path, the interface 16 fit tightly so that little air or possibly even dust can get in a disturbing manner between these surfaces. But then there is a risk of interference between the two closely adjacent opposite surfaces. The gap between the mirror 17 and the interface 16 must therefore not be too narrow. It should be more than 1μm in any case and better than 5μm.

As a comparison of Figs. 1 and 2 shows, the beam paths in the two distal lens parts 6 and 9 are identical except for the fact that in the second distal lens part 9, a double reflection takes place, whereby the beam path in the illustrated in Fig. 1 Manner is designed. This results in the same image orientation in both cases. If this is done at picture level 4 In the case of the illustration of FIG. 1, if the image is upright, then it is also upright in the case of the illustration of FIG. 2.

FIGS. 4 and 5 show an objective 1 'in a second embodiment. The objective 1 'provided for installation in the distal end region of an endoscope shaft, not shown, is shown in a highly schematic representation of its essential components.

A proximal objective part 2 'is aligned with its axis 3' on an image plane 4 ', which is the photosensitive plane of an electronic image sensor 30 in the illustrated embodiment. This is connected in a manner not shown via electrical lines to image processing equipment. Instead of the image plane 4 'of the image sensor 30, the distal end surface of a Bildleitfaserbündels can be arranged, with which the image is transported over the length of the endoscope.

The objective 1 'has two distal objective parts for different viewing directions. A first distal objective part 6 'in the highly schematically illustrated embodiment consists of a lens part 31 and a plane plate 32 which is traversed by the axis 8' of the first distal objective part 6 'perpendicular to the plane-parallel end faces.

As can be seen from FIG. 4, the axis 8 'of the first distal objective part 6' coincides with the axis 3 'of the proximal objective part 2'. In conventional construction, this axis is parallel to the longitudinal axis of the endoscope shaft, so that the first distal objective part 6 'looks straight ahead.

Between the proximal objective part 2 'and the first distal objective part 6' there is a distance in the direction of the optical axis in which a prism 14 'is arranged. Transverse to the axis 3 'of the proximal objective part 2', the prism 14 'in the direction of the double arrow 33 is displaceable. For this is z. B. a carriage guide, not shown, provided in the housing, not shown, Asked carriage guide provided in the housing, not shown, or the holder of the lens 1 ', is arranged. The drive for the displacement can be done by manual operation or with an example electric motor.

In the direction of the double arrow 33 lying one behind the other, the prism 14 'has two areas, namely a first area 34 and a second area 35.

The first region 34 of the prism 14 'is formed as a flat plate. A distal planar surface 36 and a proximal planar surface 37 are perpendicular to the axis 3 'of the proximal objective part 2'.

4, the prism 14 'is in a sliding position, in which the beam path coming from the first distal objective part 6' runs on its way to the proximal objective part 2 'through the plane-parallel first region 34 of the prism 14.

The second region 35 of the prism 14 'has the same continuous proximal planar surface 37 as the first region 34. Distally, however, it has oblique surfaces, namely an internal reflection reflecting surface 38 and an exit surface 39, in front of which a second distal objective part 9' is arranged is.

FIG. 5 shows the objective 1 'in a position in which the prism 14' is switched to another position in such a way that now the second region 35 of the prism 14 'is located distally in front of the proximal objective part 2'. The beam axis illustrated in FIG. 5 extends from the axis 10 'of the second distal objective part 9' after reflection at 40 at the proximal plane surface 37 of the prism 14 'and after reflection at 41 at the distal oblique surface 38 into the axis 3' of the proximal objective part 2 '. The inner reflection points at 40 and 41 may be formed in the embodiment both totally reflective. In the position of FIG. 5, the image sensor 30 therefore looks at an oblique angle through the second distal objective part 9 'while, in the position of FIG. 4, it is looking straight ahead through the first distal objective part 6'.

As the comparison of Figures 4 and 5 shows, the second proximal objective part 9 'is connected for common movement with the prism 14'. The connecting means are not shown in the drawing. The remaining assemblies 6 ', 2' and 30 are in turn attached to each other, as the comparison of Figures 4 and 5 shows.

In unillustrated, modified embodiment may, for. B. the second distal lens part 9 'permanently in the position of FIG. 5 and be firmly connected to the components 6', 12 'and 30, while the prism 14' is movable independently of all other components in the direction of the double arrow 33. In an alternative embodiment, both distal objective parts 6 'and 9' can also be connected to the prism 14 'for joint movement. There are given in this way constructive variations that z. B. for structural reasons or reasons of space may each have their advantages.

As can be seen from the comparison of FIGS. 4 and 5, care is taken in the illustrated objective 1 'that the optical path length, which is also referred to as "optical path" or "light path", is the same in both viewing directions. A comparison of FIGS. 4 and 5 shows that, although the optical path length through the prism region 35 of the prism 14 'is substantially longer than that through the plane plate region 34, this is compensated by the plane plate 32 in the beam path illustrated in FIG. which can be dimensioned such that actually in both beam paths of Fig. 4 and 5, the optical path length is the same.

Claims

Us. Sign: 05118ρctObjective with two directions of view for an endoscopePATENTIAL CLAIMS:

1. Lens (1, 1 ') with two viewing directions (8, 10, 8', 10 ') for an endoscope, with a first distal lens part (6, 6) aligned with its axis (8, 8') in the first viewing direction '), a second objective part (9, 9') aligned with its axis (10, 10 ') in the second viewing direction and with one with its axis (3, 3') on an image sensor (4, 4 ') or an image guide aligned proximal objective part (2, T), as well as with a prism (14, 14 ') having switching means for switchable deflection of the beam path from the first or the second distal objective part (6, 6', 9, 9 ') in the proximal objective part (2, 2 '), characterized in that the switching device has a mechanically be brought into the beam path beam deflecting means (17, 35).

2. Lens according to claim 1, characterized in that in both viewing directions (8 ', 10'), the optical path length through the lens (I ¹ ) is the same.

3. Lens according to one of claims 1 or 2, characterized in that the beam paths in the two distal lens parts (6, 9) are identical except for required reflections.

4. Lens according to one of claims 1 to 3, characterized in that the prism (14) receives the beam paths of the two distal lens parts (6, 9) and united in the proximal objective part (2) and directed obliquely to the axis (3). of the proximal objective part (2) extending boundary surface (16), wherein the beam path of the first distal lens part (6) through the interface (16) enters the prism (14) and the beam path of the second distal lens part (9) by means of reflection in the area the interface (16) is reflected back into the prism (14) to enter the proximal objective part (2), and wherein in the region of the interface (16) there is provided a movable mirror (17) which selectively moves the passageway through its movement through the interface (16) releases or causes the reflection at the interface (16).

5. Lens according to claim 4, characterized in that the prism (14) is designed according to shape and material such that at the interface (16) no total reflection occurs.

6. Lens according to one of claims 4 or 5, characterized in that a glass rod (22) of the first distal lens part (6) at a distance of a first gap (16, 21) parallel to the interface (16) lying outlet surface (21) in that the glass rod (22) is divided by a second gap (24) which lies at an angle to the axis (8) of the first distal objective part (6) which is 180 ° minus the angle of the first gap (16, 21). is.

7. Lens according to one of claims 4 to 6, characterized in that the prism (14) on its proximal to the objective part (2) lying downstream exit surface (15) adjacent to the exit region is formed inwardly reflective.

8. Lens according to claim 7, characterized in that the prism (14) in the reflective region of the exit surface (15) is formed totally reflecting.

9. Lens according to one of claims 4-8, characterized in that the distance between the mirror (17) and the interface (16) is greater than lμm.

10. Lens according to claim 9, characterized in that the distance is greater than 5μm.

11. Lens according to one of claims 4 - 10, characterized in that the mirror (17) with an adjacently arranged aperture (19) parallel to the interface (16) slidably arranged structural unit (18).

12. Lens according to one of claims 1 - 3, characterized in that the prism (14 ') has two alternately engageable in the beam path regions (34, 35), of which a first the beam path from the first distal objective part (6') and a second one guides the beam path out of the second distal objective part (9 ') into the proximal objective part (2').

13. Lens according to claim 12, characterized in that the proximal objective part (2 ') and the first distal objective part (6 ¹ ) in the same axis (8', 3 ') are arranged and the prism (14') is arranged between them , wherein the first region (34) of the prism (14 ') is formed as a plane plate, while the second region (35) at an angle (40, 41) deflects the angle between the second viewing direction (10') and the axis (3 ') of the proximal objective part (2 ¹ ) corresponds.

14. Lens according to one of claims 12 or 13, characterized in that the prism (14 ') transversely to the axis (3') of the proximal objective part (2 ') slidably disposed between the latter and the distal lens parts (6', 9 ') is.

15. Lens according to one of claims 12 - 14, characterized in that at least one of the distal lens parts (6 ', 9') is attached to the prism for joint movement.